We can easily find claims like that all around the world. Virtually, EVERYWHERE! Online or Offline. So called carbon steels, the low alloy carbon steels only contain extremely low amount of hard particles(usually the Metal Carbides, excluding Fe carbide). So they are really easy to grind, means effortless achieve of high removal rate. Knives made of such materials take much less time to get a well-sharpened state from a significantly damaged/dull state compare to high alloy steel ones, especially when the abrasive used in the whetstone is of poor hardness such as a natural stone=primitive stone. And the shorter the working time, the easier to obtain better results (=more controlled angle deviation range) relative to the operator's skill (own ability to maintain angles of working piece). When people get used to this kind of short working time and use of conventional whetstones (Diamond x, CBN x, ceramic and natural stone = primitive whetstone, etc.), even if they bring some high-all...